Carbonizing compound and process of making and using it



Sept. 9*; 1 924. f 1,507.845

/ S. B. MATHEWSON ET AL CARBONIZING COMPOUND AND rRocEss OF MAKING ANDUSING IT Original Filed April 5, 1922 III/l IIIIIIIIIII III/II gwumtozsz549,274 now Patented Sept. '9, 1924.

JUNITED- STATES PATENT ornca.

STANLEY B. ILATEEWSON AND W LTER x. JAMISON, E SPRINGFIELD, onro, As-

sIGNoEs To wALTEE x. JAMISON, STANLEY n. MATHEWSON, HOWARD F. MARS- ToN,MRS. w. x. JAmsoN, AND mas. s. B. MATHEWSON TRUSTEES on THE LECAR cAEBoNCOMPANY, A TRUST ESTATE, or SPRINGFIELD, OHIO.

omomzme COIPOUND AND PROCESS or MAKING AND USING IT. A

To all whom it may concern:

Be it 'known that we STANLEY B.

MATHEwsoN and'WAIJrER J MIsoN, citizens of the United States, residingat 6 Springfield, in the county of Clark and State of Ohio, haveinvented certain new and useful Improvements in Oarbonizing Compoundsand Processes of Making and Usin Them, of which the following is a 10speci cation, reference being had therein to the accompanying, drawing.j

Our invention relates to a carbonizing compound and the process ofmaking it and using it for carbonizing'metal, and in par- 1 ticular casehardened steel. The object of our invention is to utilize scrap leatherby the treatment'of our invention hereinafter described and claimed.

' An additional object, of our invention. is to provide a new product bythis treatment which may be utilized as a carbonizing material. 1

It is a further object of our invention to provide a method-of utilizingour new prodnot incase hardening metals such as steel inorder to provideavery deep case in the minimum of time and economically.

This is a division of application No. Patent 1,471,563, of October 23,1923.

Referring to the drawings:

1 is a carbonizing can;

furnace in which the carbonizing can is placed with the scrap leather inorder to reduceit to the form ofthe product now in question;

Fig. 3 is a diagrammatic view of the rolls and screen for determiningthe size and grade of the resulting carbonized product;

Fig. 4 is a crossasection of a piece of steel before treatment with thiscarbomzmg material; ,1 I

Fig. 5 is a similar view after carbomzation showing the case. Q, n

, Fig. 6 is'a section. of a carbonizmg' box packed with the carbonizingmaterial 1nvolved herein showing the articles beingcarbonized and thearrangement of their packing. It W111 be,understood that the forego ngdrawings ar diagrammatic merely and are only for the purpose ofillustration.

Referring tothedrawings in detail, 1 is a carbonizing can or metalcontainer havin a lid 2 with apertures 3 in the lid thereoi Serial no.549,274. Divided. and this application filed August 7, 1922. Serial No.580,225.

The scrap leather is placed in'this can and v the can is placed in anoven 4. This-oven 1s heated by any desired meansv as for in,-

stance by burnerssuch as at 5. It will be understood thatthisillustration of the. burners is typical only and that any kind ofheating apparatus I may be employed. The cans are covered and the lidsare tight fitting. The openings 3 are provided in --sealed with theexception of the regular ventilation therefor. It is customary to allowthe furnace to remain closed for about six hours, after which time thecontainers can be removed and the finished product may be removed fromeach one of the individual containers. It is thenv crushed between therollers 66 and screened by the screen 7 which is preferably about of amesh. The purpose of this is to reduce it .to'a suitable size forcarbonizing purposes. Flg. 2" is a 'diagrammatlc view of the Process ofhardening steel.

The finished product thus secured is used as follows. The parts to becarbonlzed are thoroughly cleansed in an alkali solution- The top of thebox is sealed with fire clay as at 11. It is the preferred practicetoplace a layer of the carbonizing material,

then a' layer of parts separated from one another by the carbonizingmaterial, a layer "of carbonizing material and another layer of parts,andso on. The whole packlng is covered with a layer of the carbomzmgmaterial;

5 the cans to permit of the adjustmentof the' internal pressure and topermit of the escape been brought up to If desired the lid may be ofmetal and sealed with fire clay. Any common practice of this sort maybefollowed. The boxes are then placed in a carbonizing furnace and thetemperature brought up to 1700 de ees F. and held at this temperaturefor a ut three hours but this time and temperature varies upon the depthof case desired, the size of the parts to be carbonized and the size ofthe carbonizing boxes.

In theevent the furnace is cold when the boxes are placed therein aproportionatelygreater time will be necessary to effect the esiredresult.

The boxes emplo ed are usually about eight and one-hal inches indiameter eleven inches deep and walls about thick. It takes about threehours to bring a hot furnace up to the temperature of 1700 degrees, thetemperature used for carbonizing.

For instance, in the case of carbonizing, S. A. E. 10 20 steel, it hasbeen found good ractice with this carbonizing material to iiold thecarbonizing heat at 17 00 degrees F. for five hours when packed in a boxof the above mentioned dimensions in order to obtain a depth of case.

The preferred method after this tempera- I ture has been maintained thisdesired length of time is to allow the case hardened steel parts to coolin the carboni'zing boxes beforethe are exposed to the air.

%e do not desire to confine our invention to any particular type offurnace for the heat treatment. An open type furnace may be employed inwhich the temperature has 1450 degrees F. beforethe parts are placed inthe furnace. It will twenty minutes to bring a part, speaking in termsof diameters, up to 1450 degrees.

The parts are then removed and quenched in brine or oil. It will beunderstood that these parts are always removed from the ace and quenchedon the rising heat.

In the second method. a salt bath maybe used and the parts are immersedin this solution. After the solution has been brought up to 1450 degreesF. the parts are removed and quenched in brine or oil. This type offurnace is usually designated a-cyani e fur- I nace. It will beunderstood that thefire does not come in direct contact with the I workas a cast iron tank is placed in the furnace and the salt, solution isplaced in the tank and melted by the heat coming in contact with'theoutsideof the tank.

It will be further understood that it is Eereferred by us that allquenching solutions retained at as low a temperature as ble, which isaccomplished by any well known means such as circulating the solutionthrou h coolin coils.

Re erring to igs. 4 and 5, 12 i a specimenofsteeland 13 isthecase.

be case hardened.

' apfiroximate.

pon analysis the ash will usually dovelop a ferric oxide color. Thevolatile matter consists of various gases. In these gases a varyingamount of ammonia will be found and the usual reaction to litmus will bealkaline. a

- While we have shown and described certain features as constituting ourinvention, it will be understood that parts have been shown for purposesof illustration only, and that we do not desire to avmg thus fullydescribed our invention, what we claim as new and desire to se cure bLetters Patent, is:--

' 1. he process of case hardenin metals consisting in heating the metalin t e presence of carbonizing material consisting. of ash moisture andfixed carbon containing material volatilizable b the heat to carry thecarbon into the sur ace of the metal to be case'hardened. i

' 2. The process of case hardening metals 1 consisting in heating themetals m an air tight vessel in thetpresence of carbomzm materialconsisting of ash moisture andfix carbon containing materialvolatiliaable by 3. The process of case hardening metals '110 consistingin heating] the metal. in an airtight vessel'to approximately 1700 F. nthepresence of car onizin materialconsisting of ash moisture and xedcarbon, the last-- containin material volatilizable by the heat to carryis e carbon into the surface of the metal to be case hardened.

4. The process of case hardening metals consisting in heating the metalin an 'a1r-' tight vessel in the A material to a temperatureapproximately 1700? F., the carbonizing material'contaming ammoniacalvolatilizable gases to carrythe carbon into the surface 0 the metallic y125 In testimonywhereof, we aflix our sigmatures. 4

STANLEY BQMATHEWSoN. WALTER x. JAMISON.

be limited to such '90 details, as obvious modifications will occur) tolpersons skilled in the art.

presence of carbonizing

